Yes, a child or guardian may enroll a parent as long as this person is serving as Power of Attorney (POA), a translator or a witness for the online enrollment form.
Keep in mind, for someone serving as POA and who is enrolling an individual for Medicare Advantage or prescription drug plans, he or she must be capable of making healthcare decisions. This person is also referred as a "Durable Power of Attorney for Healthcare" or a "Healthcare Power of Attorney."
If the POA is enrolling someone into a Medicare Supplement Plan, he or she must be capable of making insurance decisions. This person is also referred as a "Durable Power of Attorney" or a "Power of Attorney."